The present invention relates to equipment of the type used in surveying and construction, and, more particularly, to a detector device for such an application which detects the position or level of a reference plane defined by a rotating laser beam.
Rotating laser beams are commonly used in the fields of civil engineering, construction, agriculture, and surveying to establish a reference plane of light. U.S. Pat. No. 5,033,847, issued Jul. 23,1991, the disclosure of which is incorporated herein by reference, illustrates a laser transmitter which provides such a rotating reference beam. A variety of detection schemes are utilized to provide an indication of the position or orientation of a reference plane of light. For example, U.S. Pat. No. 4,676,634, issued to Peterson on Jun. 30, 1987, U.S. Pat. No. 4,693,598, issued to Sehr on Sep. 15, 1987, and U.S. Pat. No. 4,907,874, issued to Ake on Mar. 13,1990, the disclosures of which are incorporated herein by reference, each teach this type of laser detection device. These types of detection devices are typically battery-powered, particularly when employed in applications where conventional electric power lines are not readily available. Thus, battery life is an important factor affecting the utility of the device and the efficiency of those utilizing the device. Accordingly, there is a need for a battery-operated light detection device that maximizes the life of the battery power supply without unduly compromising its light detection operations.